Carbon black, which is made by the pyrolytic decomposition of hydrocarbons, is collected from a carbon black-containing smoke by filtration methods. This procedure produces carbon black in a flocculent form. In order to enhance the ease of handling of such carbon black, both in the packaging and in the ultimate use of such carbon blacks, it has been the practice to pelletize the carbon blacks.
Various kinds of pelletizers and various methods of pelletizing carbon black are known in the art. One very successfully employed pelletizer comprises a cylindrical housing and a pin shaft rotationally arranged in said housing. Carbon black and pelletizing liquid are introduced by means of openings in this housing into the space between the shaft and the housing. The pinned shaft is rotated whereby wet carbon black pellets are formed.
It has also been proposed to provide a carbon black pelleter with a hollow shaft and with open ended conduit-like pins communicating with the hollow interior of the shaft. This has been proposed for the injection of fluid material at high speeds toward the housing wall in order to prevent a buildup of carbon black cake. However, the construction of such a pelleter is difficult and the costs for such a pelleter are correspondingly high. Furthermore, the replacement of such hollow pins in fluid communication with a hollow shaft is rather cumbersome. Furthermore, the hollow pins arranged over the entire length of the shaft cannot be used for the injection of the entire quantity of the pelleting liquid because it is important for the pelleting process that the flocculent carbon black and the pelleting liquid be present in the proper relative amounts right at the beginning of the pelleting operation or in other words, at the upstream end of the pelleter.
It would, therefore, be desirable to have a carbon black pelleter available in which the pelleting liquid can be injected in a manner to achieve a fast and very efficient mixing of the dry flocculent carbon black and the injected liquid, and in which this injection and mixing can be achieved in the upstream portion of the carbon black pelleter.